• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.422-423
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• 1994

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.527-537
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• 1995

The effect of calcitonin gene-related peptide (CGRP), substance P (SP) and electrical stimulation of the tooth on the intradental nerve activtiy (INA) was investigated in anesthetized cats. The INA was recorded from single pulp nerve units dissected from the inferior alveolar nerve under stereomicroscope. The INA elicited by 3 minute application of 4M NaCl in deep dentinal cavity was compared before and after stimulation at 10 minute intervals. The magnitude of INA was calculated as the total number of nerve impulses produced in given period, and the changes of INA are expressed as % of control INA. The results obtained were as follows. 1. 16 single pulp nerve units were classified as 14 $A{\delta}$-fibers (3.4~19.4m/sec) and 2-fibers (1.5~1.7m/sec) according to the conduction velocity. 2. 4M NaCl evoked an irregular bursts of spikes which continued until washing out. Isotonic saline did not affect INA to subsequent applications of the hypertonic NaCl solution (P>0.05). 3. Local application of CGRP ($200{\mu}g$/ml) in deep dentinal cavity reduced the INA induced by 4M NaCl in $A{\delta}$-fiber units (P<0.01) and some units of those responded to CGRP during application. 4. Local application of SP ($100{\mu}g$/ml) in deep dentinal cavity reduced the INA induced by 4M NaCl in AS-fiber units (p<0.05), but increased the INA in C-fiber unit coincided with large reduction of the INA of $A{\delta}$-fiber units. 5. Monopolar electrical stimulation applied to the crown at intensities high enough to excite C-fibers (12V, 5ms, 10Hz, 10~30min) decreased the INA in $A{\delta}$-fiber units (P<0.01) and systemic pretreatment with phenoxybenzamine (3mg/kg, i.v.) enhanced this inhibitory effect (P<0.01). On the contrary, electrical stimulation increased the INA in C-fiber unit.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.528-533
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• 2008

Cavity in the mold is exposed to high pressure during injection molding operation. Injection molded articles with deep depth are often demanded as design variety increases. Subsequently mold becomes weak and deformation increases as the mold depth increases. Thus the injection molds for deep depth articles should be designed to hold out high pressure or stress concentration and large deformation. Through this study, equation for mold design was examined and suggested novel method to determine equation for mold design with deep depth. Novel equation developed in this study was modified from beam theory considering cantilever and two points bending situation while previous equation was modified from just cantilever bending situation. The validity of novel equation was verified through computer simulations for various mold side and wall thickness.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.301-304
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• 2008

The cavity of mold is exposed to high pressure during injection molding operation. Injection molded articles with deep depth are often demanded as design variety increases. Mold becomes weak and deformation increases as the mold depth increases. Thus the injection molds for deep depth articles should be designed to hold out high pressure or stress and large deformation. Through this study, equation for mold design was examined and suggested novel method to determine equation for mold design with deep depth. Novel equation developed in this study was consisted with cantilever and two points bending while previous equation was modified from just cantilever bending. The validity of novel equation was verified through computer simulation.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.149-153
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• 2008

The cavity of mold is exposed to high pressure during injection molding operation. Injection molded articles with deep depth are often demanded as design variety increases. Mold becomes weak and deformation increases as the mold depth increases. Thus the injection molds for deep depth articles should be designed to hold out high pressure or stress and large deformation. Through this study, equation for mold design was examined and suggested novel method to determine equation for mold design with deep depth. Novel equation developed in this study was consisted with cantilever and two points bending while previous equation was modified from just cantilever bending. The validity of novel equation was verified through computer simulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.221-221
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• 2009

• The Korean Journal of Physiology
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• v.1 no.2
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• pp.157-168
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• 1967

The entry of antipyrine and urea from the peritoneal cavity of rabbit into organ tissue and blood plasma was studied. Two hundred mg of antipyrine plus 300 mg of urea in 10 ml Ringer's solution was injected into the peritoneal cavity of anesthetized rabbit. The injection was made from above of a rabbit kept tying right side down and it enabled part of the abdominal organs (liver, intestine, kidney) was immersed in the injected solution and kept high concentration gradient throughout the experimental period. The remaining part of the organs was revered only by a thin film of the test solution. Subsequently, in this part of the organs the concentration gradient of the diffusible substances during entry was presumed to decrease as time elapsed. Four pieces of the liver tissue were taken namely, the right superficial, right deep, left superficial and left deep portions. Two were taken from the small intestine, one from the portion which was immersed in. the fluid and the other from that above the fluid mass. Both kidneys were separately analyzed. As a remote organ the gastrocnemius muscle was taken from the right leg of the animal. The intervals which were the time periods elapsed after injections were 5,7,10,15 or 30 minutes. At each point 5 animals were sacrificed and the concentrations of the test substances in the tissue water were measured. The results obtained were as follows. 1. In the liver the right portion which was immersed in the fluid showed higher concentration if the test substances than the left portion and the superficial region exceeded the deep region. The concentrations diminished as the time elapsed after infusion, particulary in the case of antipyrine, suggesting circulatory removal of the substances. In urea such decreasing tendency of the concentration was not obvious, and suggested slower removal rate of it as compared with that of antipyrine. 2. In the small intestine there was no regional difference in the concentration of the test substances. Because of the intestinal motility different portions of the intestine were seemed to have bathed in the fluid of the same concentration. In general the concentrations in the intestinal wall exceeded those of the liver, suggesting a slower removal rate than in the latter. 3. In the kidney the accumulation of the endogenous urea was predominant, and the accumulating mechanism in the renal tissue went on during the period of the experiment. Therefore it revealed increasing tendencies as the time elapsed. The penetration of the test substances in this organ from the peritoneal cavity seemed to be slower than in other abdominal organs, namely liver or small intestine. Part of the test substances in the kidney were obviously brought by the blood stream. 4. Rapid exponential decay of the concentration of antipyrine and of the osmolality of the peritoneal fluid was attributed to the extensive removal through the whole dimension of the peritoneal surface, and the remote organ such as the gastrocnemius muscle attained a fairly close value to that of the abdominal organs in less than 30 minutes. The factors which related to the absorption rate were discussed. They were the concentration gradient, permeability and the regional perfusion rate.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.133-137
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• 1982

Radiography is one of the important tool adopted in daily dental practice and medical diagnosis. To visualize soft tissuechange various contrast media has Been introduced. Any cavity or space can be easily determined by increasing the X-ray absorption of the cavity using the radiopaque contrast media which widely employed in medical radiography to show much of the digestive, cardiovascular, pulmonary, and renal system. The essential part of any radiopaque medium is a heavy element that can absoarb most of the X-ray beam. The element must be noninjurious and easily eliminated. Both aqueous and oil suspensions of iodine containing compounds' are available to the dental profession, for example Lipiodol and Dionosil. The study was designed to determine toxic effect of Lipiodol to the vital pulp and to confirm visualization ioprovement in pulp canal. 1. Thin mixture of Calcium hydroxide and Lipiodol was applied to 19 deep vital cavities for 24 hours. Only one case complained slight pain for short time. 2. Cotton pellet over-saturated in Lipiodol was inserted in coronal chamber of which 6 were non vital and 5 were vital. The transference of Lipiodol was not noticed in every case after 24 hours. 5 cases with vital pulp tissue in the canals showed no clinical symptome. 3. Extracted 20 teeth were routinely prepared for endodontic treatment and applied Lipiodol in conjunction with cotton fiber as deep as midportion of the roots. After 24, hours the medicament reached to nearly the end of apex, but there were no evidence of penetration in dentine layer and migrate into ramified canal.

• Journal of Oral Medicine and Pain
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• v.41 no.4
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• pp.195-199
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• 2016

Central sensitization represents a functional change of second order neuron induced by continuous deep pain input and maintained by psychosocial factors. When afferent neurons are involved with central sensitization, secondary hyperalgesia can appear. Secondary hyperalgesia is an increased sensitivity to stimulation without a local cause. Reports on secondary hyperalgesia to heat stimuli are relatively rare compared to mechanical stimuli. And there were few reports of secondary hyperalgesia to heat stimuli in the oral cavity. We presented a case of secondary hyperalgesia to heat stimuli in the gingival area induced by continuous odontogenic pain with a review of the related literature.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.4
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• pp.194-200
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• 1997

A two-dimensional shallow-water flow around a cavity driven by a sinusoidally oscillating external flow was studied numerically. A container model of "T" shape was constructed in the numerical computation for comparison with the experimental observation. The numerical computation shows that the aspect ratio of the cavity is not much affecting the overall flow pattern, and for the aspect ratio 2, the deep region of the cavity has a stagnant flow motion. At larger Reynolds number, the flow field is characterized by many small vortices which are not present in the flow visualization. The flow pattern in the external region is in good agreement with the experimentally recorded particle trajectories. It turns out that two large coherent vortices situated in the exterior region of the cavity are responsible for clockwise and counterclockwise drift motions, in large scale, of particles.particles.